This invention relates to an automobile seat with a backrest frame and/or a seat frame, each of which has open side braces placed laterally and essentially U-shaped in cross section.
Frame constructions with side brace hollow profiles open on one side are known. They are used primarily with small thicknesses to reduce weight. Of course, special measures are necessary to make such side brace hollow profiles rugged and torsionally rigid. This applies particularly to the side braces of backrest frames, to the top of which a safety belt may also be fastened.
As measures for achieving the desired load capacity and torsional rigidity of the side braces, it is known how to give side braces, generally made of rod material, a special cross sectional profile, which can be symmetrically C-shaped, U-shaped, or Z-shaped for example. It is also known how to arrange the side braces of backrest frames so that the axis of the largest moment of resistance points approximately in the direction of action of the safety belt, i.e., diagonally to the long direction of the seat (cf. DE-OS 36 24 295). However, this then results in a larger structural volume for the backrest which is inherently desired to be particularly flat, and a smaller moment of resistance in the direction of the forces acting approximately perpendicular to the backrest that are especially large in the area of linkage of the backrest frame to the seat bottom and/or to the seat frame.
It is the purpose of this invention to propose a design for the side braces of the backrest frame and/or of the seat frame that can absorb high forces from all important directions of application, and at the same time is torsionally rigid and nevertheless does not require a larger structural volume for the seat, and particularly not for the backrest desired to be of flat design.
This problem is solved pursuant to the invention by the fact that the open side of the side braces extends away from the top of the seat used by the passenger and that the back of the side braces facing the passenger has such a large width, at least in some areas, that structural adjusting units for the seat can be placed in the cavity enclosed by the side braces, i.e., in the inner profile space of the side braces. It is desirable to provide that the adjusting units located in the profile space are fastened to both side walls of the side brace.
Particularly beneficial side braces pursuant to the invention also have a diagonal surface that is placed at the center of the seat, and a side brace back width that changes relative to the backrest frame, which decreases essentially conforming to the outer contour of the backrest starting from the bottom of the side braces toward the head of the backrest frame.
With regard to the backrest frame, it is beneficial also to modify the structural depth of the side braces, specifically increasing toward the bottom of the side braces. At this bottom end of the side braces, i.e., at their base, the pivot axis is then shifted forward toward the passenger for the tilt adjustment of the backrest, i.e., it is located next to the back of the side braces. On the other hand, the linkage points of the tilt adjusting mechanism are then to be positioned on the side braces toward the rear, i.e., away from the passenger next to the open side of the side braces. This results in a particularly effective linkage of the side braces of the backrest frame to the seat bottom or the seat frame that can handle all forces properly.
As a result, the construction pursuant to the invention provides that the side braces have a wide back profile with a wide inner profile space to hold adjusting units for the seat, and at the same time because of the diagonal surfaces designed in them and because of a certain outer contour shape, and also because of the mentioned structural depth modification toward the deep and wide base of the side braces, they constitute a polyhedral object that can absorb large forces from all important directions of application with torsional rigidity.
The placement of the adjusting units for the seat in the inner profile spaces makes it possible for the structural volume of the seat to remain small in the desired manner. This applies particularly to the desired flat design of the backrest, which undergoes no enlargement of the backrest thickness in the particularly critical central area of the backrest because of the integrated placement of the backrest adjusting units in the cavity of the side braces on the outside and at the side.
An additional extreme reinforcement of the side brace hollow profile is achieved at the same time by the integrated placement of the adjusting units for the seat, for example a latching unit, an adjusting motor, or the like, in the inner profile space of the side braces, and the simultaneous fastening of the adjusting units to both side walls of the side brace.
Nevertheless, the large back widths of the side braces necessary for the utilization of the inner profile space do not interfere with seat comfort, since the backs of the side braces have a diagonal surface located at the center of the seat that brackets the backrest and/or the seat surface for the body of the passenger and at the same time supports the body of the passenger on the side.
The "polyhedral object" described above as a side brace for automobile seats is a new design principle that intentionally avoids the use of extruded, canted, or rolled bar profiles for the side braces of backrest frames and/or seat frames. Nevertheless, the polyhedral object can be manufactured economically from sheet metal by means of a form tool, for which the light construction can be taken into account by appropriate optimization of the sheet thicknesses.
With regard to the side braces of a seat frame, a desirable refinement of the invention provides that a second brace (called the bottom brace below) is arranged beneath each of the side braces of the seat frame with U-shaped cross section open at the top, and that the side braces are adjustable relative to their bottom braces by adjusting units that are located in the cavity enclosed by the side braces.
It is particularly desirable for the side braces to overlap the bottom braces with each outer side wall. The bottom profile can be almost completely covered over by this, and the side wall of the side brace drawn downward can advantageously be used for the attachment of handles or other manual operating devices, without the risk that the hand of the passenger will get between the side brace and the bottom brace.